More than half of all women with infants under one year are employed outside the home. Their infants experience a variety of forms of nonmaternal care. Recent research suggests that children who begin nonmaternal care in the first year are at risk for insecure attachment and non-compliance, characteristics which may make them more likely to develop learning, emotional and behavior problems in later years. It is not fully understood, however, how factors associated with nonmaternal care affect these outcomes. The proposed project will compare the quality of mother- child mutual adaptation in the second year for dyads with and without mothers who are employed during the infant's first year. It will also determine the individual, familial and environmental factors related to differences in mother-child mutual adaptation within mother-employed and mother-at-home groups. The proposed project is a prospective, longitudinal study in which primiparous couples will be recruited prenatally. Mothers and infants will be observed at home quarterly in the first year. Infants whose mothers leave them in nonmaternal care will be observed in that setting two weeks after onset and quarterly thereafter. The quality of caregiving at home and in daycare will be measured with a coding scheme tapping sensitive and appropriate responsiveness to infant signals. Mutual adaptation, a construct consisting of attachment security, the control-autonomy balance in the mother-child relationship, and interactive quality will be assessed at 12 and 18 months. This method will permit a validation of the use of the Strange Situation as an assessment of attachment security for infants experiencing regular non- maternal care. A model will be tested in which the effects of nonmaternal care are mediated by infant vulnerability to variations in maternal caregiving, which in turn is subject to individual, familial and environmental influences.